From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:34028 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750998AbdCLFVC (ORCPT ); Sun, 12 Mar 2017 00:21:02 -0500 Date: Sun, 12 Mar 2017 06:20:48 +0100 From: Greg KH To: Jiri Slaby Cc: tiwai@suse.de, stable@vger.kernel.org, stable-commits@vger.kernel.org Subject: Re: Patch "ALSA: ctxfi: Fallback DMA mask to 32bit" has been added to the 4.4-stable tree Message-ID: <20170312052048.GA22384@kroah.com> References: <14889688267226@kroah.com> <64decc2d-e459-476a-f344-a191f09ebec0@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <64decc2d-e459-476a-f344-a191f09ebec0@suse.cz> Sender: stable-owner@vger.kernel.org List-ID: On Sat, Mar 11, 2017 at 04:28:53PM +0100, Jiri Slaby wrote: > On 03/08/2017, 11:27 AM, gregkh@linuxfoundation.org wrote: > > From 15c75b09f8d190f89ab4db463b87d411ca349dfe Mon Sep 17 00:00:00 2001 > > From: Takashi Iwai > > Date: Tue, 28 Feb 2017 17:16:48 +0100 > > Subject: ALSA: ctxfi: Fallback DMA mask to 32bit > > > > From: Takashi Iwai > > > > commit 15c75b09f8d190f89ab4db463b87d411ca349dfe upstream. > > > > Currently ctxfi driver tries to set only the 64bit DMA mask on 64bit > > architectures, and bails out if it fails. This causes a problem on > > some platforms since the 64bit DMA isn't always guaranteed. We should > > fall back to the default 32bit DMA when 64bit DMA fails. > > > > Fixes: 6d74b86d3c0f ("ALSA: ctxfi - Allow 64bit DMA") > > Signed-off-by: Takashi Iwai > > Signed-off-by: Greg Kroah-Hartman > ... > > @@ -1904,19 +1898,18 @@ static int hw_card_start(struct hw *hw) > > { > > int err; > > struct pci_dev *pci = hw->pci; > > + const unsigned int dma_bits = BITS_PER_LONG; > > > > err = pci_enable_device(pci); > > if (err < 0) > > return err; > > > > /* Set DMA transfer mask */ > > - if (dma_set_mask(&pci->dev, CT_XFI_DMA_MASK) < 0 || > > - dma_set_coherent_mask(&pci->dev, CT_XFI_DMA_MASK) < 0) { > > - dev_err(hw->card->dev, > > - "architecture does not support PCI busmaster DMA with mask 0x%llx\n", > > - CT_XFI_DMA_MASK); > > - err = -ENXIO; > > - goto error1; > > + if (dma_set_mask(&pci->dev, DMA_BIT_MASK(dma_bits))) { > > I believe the condition is inverted here. > > > + dma_set_coherent_mask(&pci->dev, DMA_BIT_MASK(dma_bits)); > > + } else { > > + dma_set_mask(&pci->dev, DMA_BIT_MASK(32)); > > + dma_set_coherent_mask(&pci->dev, DMA_BIT_MASK(32)); As this matches what is in Linus's tree, that means I didn't mess up the backport :) But I don't understand the issue, what is wrong here? Should it try 32 first? Takashi, any thoughts? thanks, greg k-h